Simple Color Picker?

have been using this question to create my own color picker:

Simple color picker

i can figure out the color from the progress of the seekbar but cant figure out how to set the progress from an entered color.

any help is appreciated.

My code so far:

package somepackage;

import android.content.Context;
import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.graphics.drawable.LayerDrawable;
import android.util.Log;
import android.view.ViewGroup;
import android.widget.SeekBar;

public class ColorPicker extends SeekBar {
    private int defaultColor = 0xFFFFFFFF, currentColor = defaultColor;
    private OnColorChanged onColor = null;

    public ColorPicker(Context context) {
        super(context);
        GradientDrawable gradient = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT, new int[]{
                0xFF000000,
                0xFF0000FF,
                0xFF00FF00,
                0xFF00FFFF,
                0xFFFF0000,
                0xFFFF00FF,
                0xFFFFFF00,
                0xFFFFFFFF
        });
        gradient.setCornerRadius(8);
        setBackground(gradient);
        setProgressDrawable(null);
        setMax(256 * 7 - 1);
        setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                Log.i("Progress",String.valueOf(progress));
                currentColor = getColorFromProgress(progress);
                drawThumb();
                if (onColor != null) onColor.onColorChange(currentColor);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
            }
        });
        drawThumb();
    }

    @Override
    public void setLayoutParams(ViewGroup.LayoutParams params) {
        super.setLayoutParams(params);
        drawThumb();
    }

    private void drawThumb() {
        int size = 0;
        if (getLayoutParams() != null) {
            size = getLayoutParams().height - getPaddingTop() - getPaddingBottom();
        }
        LayerDrawable layerDrawable = new LayerDrawable(new Drawable[]{
                Utils.getCoaster(Color.WHITE, 16, 10, size / 2, size),
                Utils.getCoaster(currentColor, 16, 10, (int) (size / 2.25), (int) (size / 1.25))
        });
        setThumb(layerDrawable);
    }

    public int getColor() {
        return currentColor;
    }

    public void setColor(int color) {
        setProgress(getProgressFromColor(color));
        drawThumb();
    }

    public void setOnColor(OnColorChanged onColor) {
        this.onColor = onColor;
    }

    private int getProgressFromColor(int color) {
        int r = Color.red(color);
        int g = Color.green(color);
        int b = Color.blue(color);
        int progress = 0;
        // Generate the progress int accordingly to the 'color' int.
        return progress;
    }

    private int getColorFromProgress(int progress) {
        int r = 0;
        int g = 0;
        int b = 0;
        if (progress < 256) {
            b = progress;
        } else if (progress < 256 * 2) {
            g = progress % 256;
            b = 256 - progress % 256;
        } else if (progress < 256 * 3) {
            g = 255;
            b = progress % 256;
        } else if (progress < 256 * 4) {
            r = progress % 256;
            g = 256 - progress % 256;
            b = 256 - progress % 256;
        } else if (progress < 256 * 5) {
            r = 255;
            g = 0;
            b = progress % 256;
        } else if (progress < 256 * 6) {
            r = 255;
            g = progress % 256;
            b = 256 - progress % 256;
        } else if (progress < 256 * 7) {
            r = 255;
            g = 255;
            b = progress % 256;
        }
        return Color.rgb(r, g, b);
    }

    public interface OnColorChanged {
        void onColorChange(int color);
    }
}

and i need help figuring out how to generate 'getProgressFromColor(SOMECOLOR)'

EDIT: added code